[cola]

Okay, I got the hold button to work. Here is the output of diff -r from the tree of koreader-kobo-arm-kobo-linux-gnueabihf-v2015.11-1523-g78284e1.zip (with inessential stuff removed):

Spoiler:

diff -r koreader/frontend/device/input.lua koreader2/frontend/device/input.lua
413a414,422
>                 self:setMtSlot(MTSlot.slot, "unused", nil)
>             end
>             self.MTSlots = {}
>             for _, slot in pairs(self.ev_slots) do
>                 table.insert(self.MTSlots, slot)
>                 if slot.unused then
>                     slot.id = -1
>                     slot.timev = TimeVal:new(ev.time)
>                 end
417a427,429
>             for _, slot in pairs(self.ev_slots) do
>                 slot.unused = true
>             end
479a492,495
>             self.MTSlots = {}
>             for _, slot in pairs(self.ev_slots) do
>                 table.insert(self.MTSlots, slot)
>             end
482a499,501
>             for _, slot in pairs(self.ev_slots) do
>                 slot.id = -1
>             end
diff -r koreader/frontend/device/kobo/device.lua koreader2/frontend/device/kobo/device.lua
107a108
>     touch_mirrored_x = false,
272c273
<         ev.value = ev.value - 1
---
>         ev.value = ev.value